This disclosure is concerned generally with means for determining the presence of Neisseria bacteria utilizing an immunoassay technique.
The importance of being able to quickly and accurately detect the presence of Neisseria bacteria, especially Neisseria gonorrhoeae, is well recognized. Conventional tests for detecting the presence of organisms such as N. gonorrhoeae involve the preparation of bacteria cultures or the use of serological methods. Such tests, however, have known limitations. See, for example, the publication "International Symposium on Gonorrhea", B. B. Diena, Ed., a collection of papers presented at the October, 1973 International Symposium on Gonorrhoea sponsored by the Health Protection Branch, Health and Welfare Canada, Ottawa, especially at p. 34 et seq.
A relatively simple and quick test for the presence of Neisseria in liquid samples which has been discovered is disclosed in the related application cited above entitled "Detecting Neisseria Bacteria". That test is founded upon the discovery of an enzyme in Neisseria bacteria which appears to be specific to Neisseria. The complete structure of the enzyme has not as yet been determined and no identification therefor has been located in the literature. However, the enzyme has been observed to oxidize 1,2-propanediol and reduce nicotinamide-adenine-dinuclectide (NAD). Tha behavior has led to the name 1,2-propanediol dehydrogenase being applied thereto, and that designation will be employed throughout this specification.
That a biochemical reaction can take place between an antigen and its homologous antibody giving rise to an antibody-antigen complex is well recognized. An explanation of that phenomenon can be found in "Immunochemistry of Enzymes and Their Antibodies", M. J. Salton, John Wiley & Sons, New York (1977). In the case of an enzyme, the reaction thereof with its specific antibody may result in inhibition of the activity displayed by the enzyme. In this manner, then, the presence of a particular enzyme can be detected by bringing the antibody specific to the said enzyme into contact with the sample in question and monitoring the result for a decrease in enzyme activity.
The instant invention contemplates the use of antibodies directed against the enzyme present in Neisseria bacteria, i.e., the 1,2-propanediol dehydrogenase referred to above, to inhibit enzyme activity in an assay sample, thereby inferring antibody specificity on the assay of the enzyme. This procedure combines the sensitivity of an enzymatic reaction with the specificity of an immunoassay.